so did we ever truly learn what pushed her off the deep end? drugs? meth? crack? religion? psychosis? all of the above?

I think to begin with, growing up without her father never helped plus she had mental issues - petit mal seizures: in some interview tapes you can visibly see that she zones out for a good 5-7 seconds before continuing the convo- all of which she bears no fault for whatsoever but the OCD she developed later on because (IMHO) of her involvement in clubs then BBing and finally with crackheads, cartels n gangs in Venice is all down to her own volition. She had advice growing up, her family wanted her to become a physiotherapist but - as I was told- with Denise being Denise: If she didn't like it and you tried to force it on her, she would tell you to f@#k off...

...and of course if you add religion into the mix, you end up with a cocktail for disaster!

Even with her pleasant demeanour (for those who met her early to mid 90s), I think she is paying the ultimate price for her stubbornness.